Location: Commodity Protection and Quality
2013 Annual Report
Postharvest decay annually causes significant losses of fresh citrus fruit and table grapes. Control of postharvest green mold of citrus caused by the fungal decay pathogen Penicillium digitatum is needed to successfully store, transport, and market these fruit. Infections occur primarily through superficial wounds inflicted on the fruit during harvest and handling operations, sometimes, one or two days elapse before the fruit pass down packinglines where antifungal treatments can be applied to manage this problem. Because managers do not know the influence of the length of this interval on the effectiveness of the packline treatments to control this pathogen, a series of experiments were conducted where the fruit were inoculated and stored at a range of temperatures before they were treated. The tests were done under controlled laboratory conditions and repeated in three commercial packinghouses. The typical packinghouse treatment sequence, developed in part from earlier work at this location, included immersion in heated sodium bicarbonate solution, passage through a heated, dilute solution of the fungicide imazalil, and lastly coated with a fruit wax containing this fungicide and a second fungicide, thiabendazole. Under conditions that were relatively temperate (15 to 20 C), an interval of 48 hours could elapse before treatment and green mold was well controlled. Under cold conditions (5 C), an interval of 96 hours could elapse before treatment and green mold was well controlled. A practical conclusion of this work is that when harvest occurs during warmer periods, proper management of the fruit indicates they should be processed within 48 hours of harvest. When harvest occurs during colder, winter conditions, the fruit should be processed within 96 hours of harvest.
Smilanick, J.L., Mlikota Gabler, F., Margosan, D.A. 2012. Evaluation under commercial conditions of the application of continuous, low concentrations of ozone during the cold storage of table grapes. Acta Horticulturae. 945:357-361.
Cerioni, L., Rapisarda, V., Doctor, J., Fikkert, S., Ruiz, T., Fassel, R., Smilanick, J.L. 2013. Use of phosphite salts in laboratory and semi-commercial tests to control citrus postharvest decay. Plant Disease. 97:201-212.
Erasmus, A., Lennox, C.L., Smilanick, J.L., Lesar, K., Fourie, P.H. 2013. Imazalil residue loading on citrus fruit as affected by formulation, solution pH and exposure time in aqueous dip treatments. Postharvest Biology and Technology. 77(1):43-49.
Obenland, D.M., Collin, S., Sievert, J., Arpaia, M. 2013. Mandarin flavor and aroma volatile composition are strongly influenced by holding temperature. Postharvest Biology and Technology. 82:6-14.